1. Field of the Invention
The present invention relates to photographic printers. In particular, the present invention is an improvement to a photographic printer which avoids waste and loss of productivity by preventing the printer from recording a photographic image on a portion of a print paper web containing a paper splice.
2. Description of the Prior Art
In commercial photographic processing operations, high rates of processing must be achieved and maintained in order to operate profitably. To expedite the photographic processing, orders containing film of similar type and size are spliced together for developing. After developing of the photographic film, a photographic printer records the photographic images in edge-to-edge relationship on a continuous web of photosensitive print paper by the photographic printer. In this type of photographic printer, the print paper web is typically advanced by a predetermined feed length during each operating cycle of the printer in order to advance the next unexposed portion of the print paper web to a printing aperture. High intensity light is passed through the film and imaged on the image area of the photographic print paper defined by the printing aperture to expose the photographic emulsion layers of the paper and record a photographic image.
After leaving the printer, the print paper web is photoprocessed to produce prints. A photographic paper cutter then cuts individual prints from the photographic web; the prints are sorted by customer order; and the prints and the corresponding film segments are packaged and sent to the customer.
One problem which has been encountered in the past is caused by the occurrence of paper splices in the web of photographic print paper. The paper splices are necessary, of course, in order to provide a web of the desired length. As the speed of photographic printers is increased and the capability of printing larger numbers of photographic prints is achieved, the problem of paper splices also increases.
In particular, a significant loss in productivity occurs when a photographic image is recorded on a portion of the print paper web containing a paper splice. The resulting photographic print is unsatisfactory, and cannot be sold to a customer. As a result, this photographic print must be remade in order to complete the customer's order. Remake prints typically are handled on a less automated basis than normal first-run production prints. The correct portion of film must be located, and the remake print must be produced, often on an individualized, and thus far less efficient basis.
It is necessary according to National Standards to provide a splice warning slot in the print paper web which precedes the splice. Both the splice and the slot can vary substantially in dimensions and relative position. In some prior art photographic printers, a sensor has been provided to sense the slot which precedes the paper splice. When the sensor detects a splice warning slot, an indication light is lit, warning the operator that a paper splice has been encountered. The operator then may take whatever action he wishes to avoid printing on the splice.